Method of forming and laying continuous concrete pipe



T. DE LA MARE l l l I I l l I l I I I l l Toms INVENTCJR,v

ATTORN EY Nov. l5, 1927.

METHOD oF FCRMINC AND LAYING CONTINUOUS CONCRETE PIPE m N w. w d. C w M N m mvw www. f| .l AI F u A d Nov. 15, 1927. 1,648,982

v T. DE. LA MARE METHOD 0F FORMING AND LAYING CONTINUOUS CONCRETE PIPE,

Filed Maron 12. 1921 s sheets-sheet 2 Nov. 15, 1927. I 1,648,982

T. DE LA MARE*- METHOD oF FORMINC AND. LAYINC CONTINUOUS CONCRETE PIPE Filed VMarch 12.- 1921 3 Sheets-Sheet 3 WITN ESSES Patented Nov. 15, 1927.

Unirse STATES PATENT OFFICE.

THOMAS DE LA MARE, OF TOOELE, "UTH, ASSGNOR TO PERCY F. MCKENDRICK, OF GARFIELD, UTAH.

llfEETI-IOD OF FORMING AND LAYING CONTINUOUS CONCRETE PIPE.

Application led March 12, 1921. Serial N0. 451,756.

This invention has reference to a method of formino concrete pipes, and its object is to lay such pipes continuously so that they are practically monolithic from one end to the other and may be of any length.

In accordance with this invention, the pipe units are made in relatively short lengths, say, from ten to twenty feet as a maximum; and the ends of the units are united in such manner as to provide a substantially monolithic structure, wherefore the pipe line is in effect a one-piece line, although provision is made for such slippage as may be advisable to prevent buckling or cracking of the cement as it dries and as it is subjected to temperature changes. y l

lt has been the custom heretofore, in laying concrete pipe, to set a gang of men at wvo/rk and build a'length of pipe by the aid of molds or forms, but since concrete pipe must harden for a certain period of time before the mold is removed, the amount of pipe which may be laid in the course of a working` day is limited to from 150 to 200 feet, according to the size of the pipe and according to the manner of laying such pipe.

By practicing this invention the amount of pipe which may be laid in the course of a day, may be gradually extended by the use of a sufhcient number of forms initially assembled in pairs, with each pair separated from the next pair by relatively long-distances and then working from the adjacent ends of companion pairs toward each other.

Because of the necessity of the formed pipe setting for a much longer time than it takes to lay it, a gang); of men may attend 'to several pairs before the laid pipe is sufficiently hard to permit the removal of the molds. In this way, many hundreds or even thousands of feet of pipe may be formed in the course of a day, making the operation very economical. Experience has demonstrated that the pipe so laid is much stronger than pipe heretofore made by any other method.

ln accoreance with the invention, tamping of the concrete is not practiced and the concrete mixed is initially in the condition known in the art as plastic or sloppy mix thus making the walls of the pipe dense without the necessity of tamping and also producing an intimate union between the lengths of pipe where they come together.

The invention will be best understood from a consideration of the following detailed description taken in connection with the accompanying drawing forming part of this specilication, with the understanding, however, that the invention is not confined to any strict conformity with the drawing, but may be changed and modified so long as such changes and modifications mark no material departure from the salient features of the invention as expressed in the appended claims.

In the drawings Fig. 1 is a'diagrammatic view illustrating the manner of forming the pipe where approaching Zones of pipe are produced to be ultimate-ly oined to form monolithic pipe.

Fig. 2 is a vertical section through one end of a finished pipe and the succeeding section of an unfinished pipe with a form in place ready for pouring, the arrangement being such as to produce pipe capable of withstanding considerable internal pressure.

Fig. 3 is a longitudinal section through the adjacent approaching ends of two pipes, showing the means of coupling such ends where the coupling is of monolithic character and capable of withstanding considerable internal pressure.

Fig. 4 is a longitudinal vertical section of a form of pipe where considerable internal pressure is not to be resisted.

Fig. 5 is a view similar to Fig. 4e, but showing a further step in the forn'iation of the joint. l

Fig. 6 is a view similar to Fig. 5, but showing further progress in the formation of the joint.

F 7, 8 and 9 are cross sections showing different stej'is in the forn'iation of the concrete pipe.

Fig. l() is a cross section through a coupling in which corrugated sheet metal is used.

F ig. 11 is a cross section showing the preferred manner of weighting down the mold with rock.

Fig. 12 is a cross section of a pipe in which reinforcement is employed.

In accordance with the method of the invention, when preparing to lay the concrete pipe, which it maybe assumed is to be laid underground, a trench which may be hundreds or even thousands of feed in length is iirst excavated.

A suitable number of molds is provided, and these molds are distributed in pairs along` the trench ready for use, at distances apart which may amount to 500 or (500 toet, more or less. lt the pipe to be made is 12- inch pipe, a gang oit about tour men is required, which can take care et from tive to siX molds. ln order to facilitate the work, water-tight mixing boxes are set up at intervals alongside et the trench and filled with sand, gravel and cement and a little clay. One man of the gang paints a mold and one dresses the trench, while two men mix the `dry concrete which is prepared in three batches in each boX. Thelirst batch, which. in quantity amounts to about onefourth olf the concrete in the mining box,

water applied thereto to soak the mixture. lhilc the soaking is progressing, the workmen are coi/'ering up the pipe, made the day beliore, with dirt. 'lhen the iirst :fourth ot the batch is thoroughly mixed and introduced into the bottom ot the trench. The mold is then placed in the trench on top of the first batch and forced down into it 'lor a short distance, wl'iereupon the second batch is mixed and poured upon the lirst batch about the sides of the mold. Following this, the third batch is mixed but with a less amount ont water to make a drier mixture, and is deposited in the trench, finally covering the mold and completing the pipe.

The sloppy or plastic mixture of concrete is such that when the temperature prevailing at the time the pipe is being formed ranges from 600 F. downward, it is necessary to keep the molds from lloating on the concrete as it is poured. For this purpose, two large flat rocks or other weights are placed in the bottom of the trench with a piece ot wire laid under them and hung up on the side of the trench temporarily out of the way while the bottom layer oi concrete is poured. Then, when the mold is set sulliciently, the two ends of each wire are brought together and secured tight around the mold so that the rocks act as weights to keep the mold from floating to the top oi' the concrete. Such rocks are placed in the bottom of the trench below the concerte and about two -licct trom either end ot the mold and are allowed to remain permanently.

lhe concrete poured into the trench about the mold and in Contact with the ground at the bottom and sides oi the trench becomes .earth-cured, while the drier mixture completing the pipe absorbs the moisture rising from the two lower layers already poured, thus helping to set the newly made pipe faster than otherwise, and also preventing any water from running along the top of the pipe and destroying the new pipe.

`When starting to lay the pipo, two forms 0r molds are usually employed in end to end engagement, or ii there be a bend contemplated in the pipe line, it is customary to start the formation ot the pipe at the bend with two molds in abutment. litter having completed the two lengths of pipe in end engagement, the gang oi' workmen goes to the next location, which may be 500 or 600 feet away from the iirst location, and repeat-s the operation, producing two or more lengths of pipe in line with the iirst two lengths, or with one or' the vtirst two lengths. l/Vhile waiting tor the second pair of lengths oii'pipe to set sutliciently, ther gang oit workmen may lay the third two lengths and so continue the operation throughout the working day. 'lhus l to 6 in. molds may be re-used, say four times in eight hours,v when the temperature ranges from O F. up yard, and 8 in., lO-in. and 12-in. molds may be re-used about three times in eight hours, while all molds trom lil-in. upwardly can be re-used twice in eight hours. Hence under the same temperature conditions a very much larger amount of concrete pipe may be formed by the method of this invention than is possible with the methods heretofore employed and with the further advantage that the pipe is tar superior.

The operations already described take about one-halt a working day, in the formation ot lQ-in. pipe and propor'ionatelyA greater or less time with larger or smaller pipe length. By such time, the iirst laid pipe has set sutliciently to permit the withdrawal ot the molds and thelatter are reset at the completed ends oli the iirst laid pipe, thereby permit-ting the formation or' turther lengths ot pipe beyond the first laid ones, thus bringing the pipe line ends closer to the previously laid pipe. This permits the laying ot some hundreds of feet ot pipe in the course of a working day by a single gang of men.

ln using concrete pipe, one of two conditions are niet with, the 'First where the water conducted by the linished pipe merely .flows from a source to the point ot' utilization, without material internal pressure, in which instance the pipe is never tull. The other condition is where the flowing water tills the pipe and exerts pressure upon its entire inner suriiace. ln either case, the pipe contracts a'tter it is molded and is afterwards subject to expansion and ycontraction due to changes in temperature and water will tlow out ot the pipe at the joints in streams corresponding to the conditions produced by such expansion and contraction. Sometimes where the temperature ditterences are large, leaks or' considerable size may occur unless provision is made to prevent. them. liVhere the pipe lengths range from l0 to 2O feet, slip joints are employed between the sections to avoid the formation o1 cracks and these slip joints are embedded in the concrete so that small differences in length, due to expansion and contraction, may occur lili) lli without causing either the cracking or, the buckling of the concrete. On making a new joint where slip joints occur, the end of the last layer should be painted or oiled to'keep the new joint from knitting to the previous joint, thus allowing' the slip joint to operate in case of contraction and expansion.

Prelin'iinary to laying the pipe, there is formed a trench 1 provided with a rounded bottom 2 (Figs. 7, 8 and 9) into which a layer 3 of concrete is poured to adepth so that when a form or mold 4 is set in the trench and the concrete is poured between the mold and the walls of the trench it rises up the sides of the trench, for a dist-ance of withdrawn and placed end to end with respect to the pipe already formed. Such a mold is designated in Fig. 2 by the reference numeral 4, and may comprise a inechanical collapsible form or may have rubber or other kiud of walls admitting of collapsing.

At the end of the pipe section from which the mold is withdrawn there is provided, in theevent that the pipe is to withstand inf ternal )ressure slia 'oint 8 Fie'. 2 comprising two telescoping members 9, 10, respectively, suiiici-ently tapere-d to permit telescoping or expansion without escape one from the other. At the end of one of the slip joint members, say the member 9, there is provided a circumferential bead 11 to hold a ring 12 of ,oakum or other appropriate material.

That end of the laid pipe containing the telescoping joint, before the joint. is extended, is built thicker than the body of the pipe to accommodate the joint, while the trench, where thejoints occur, is enlarged as indicated at 13 to reinforce the joint. Moreover, additional reinforcement indicated at 14 is provided at each joint but independent of the slip joint, this reinforcement 14 occurring in both of the abutting pipe lengths, which latter, however, may be considered as substantially integral since the slip is only sutiicient to allow for a relatively minute eX- pansion and contraction.

The body of the pipe is indicated at 15, and for all practical purposes is monolithic.

As the laying of the pipe proceeds, the ends progress in both directions until ultimately the ends come within a short distance of each other, say within about five feet, this being the assumption in Fig. 3. To finish the pipe where so closely approaching,

-1n Figs. 4, 5 and 6 is a feasible one.

there are provided two telescoping lengths 16, 17 capable of being collapsed to a greater extent than the distance between the ends of the pipe. The telescoping mold is `contracted and the ends then introduced into the approaching pipe ends, each of which has a ring 18 similar to the ring 8 and formed with a bead 19 to which is applied a packing 2O of oakum or similar material. Like the structure of Fig. 2, the ends of the pipe lengths are enlarged and provided with reinforcements 21 similar to the reinforcements 14.

The telescoping members 16, 17 are designed to form a support for a finishing sec` tion 22 of concrete and are permanently emj bedded therein.

While the pouring of the pipe is progressing, each mold 4 is provided with a closure or bulk head 23, as shown at the right hand end of Figure 2, and in the slip joint, adjacent this bulk head, the member is telescoped within the member 9. After the concrete has set, and before the next pouring is made, the bulk head 23 is removed and the member 10 is drawn out, so that it will become embedded in the next length of pipe when the latter is poured, the position after the pipe is completed being shown at the left hand end of Figure 2. As above explained, when the concrete is first poured. the ends of the sections abut, but in setting the concrete contract-s suiiiciently to leave a slight space between the ends sufficient to allow for subsequent expansion and contraction.

By forming pipe at widely separted localities with the sections proceeding in opposite directions toward the other sections, the progress of the work is very much more rapid than would occur if the pipe proceeded from one locality onward.

Vhen the pipe is not intended to withstand considerable internal pressure but simply serves as a duct for conveying' water, with the stream of water less than the capacity of the pipe, it is unnecessary to employ slip joints. The arrangement shown The trench 1 is vprovided with a layer 3 of concrete in the manner already described, and a collapsible mold 4 is set in place and slightly embedded in the layer 3. The layer 3' is succeeded by the layer 5, as shown in Fig. 8, and this layer at its upper end terminates short above shoulders 24 upon which are placed planks 25 which may substantially extend to the top of the trench. After the concrete has suiiciently hardened, the planks 25 are withdrawn, leaving the shoulders 24 eX- posed, and then the iinal batch of concrete, shown in Fig. 9 at 26, is poured, with the gap in the mold indicated at 27 in Figs. 7, 8 and 9, covered by a closure 28 to prevent the concrete from dropping into the mold, and

which closure 28 may be removed from the finished pipe at the same time that the form or mold 4 is removed.

Vhen the approaching finished pipes have come within about ten feet of each other, a layer 3 is filled into the bottom of the trench and the collapsible mold 4 of full 10ft. length is introduced into the ends of the pipes or laid so as to be supported at the ends by said pipes, a support of about one inch being enough. Then the second layer 5 is introduced, the mold 4 is withdrawn and the short mold 4a of about half the length of the full mold is placed in position, after which that portion of the pipe corresponding to the short mold is completed, and as soon as the pipe has sufficiently hardened, the short mold is withdrawn through the space next to the end of the other finished pipe.

Now, the unfinished portion which is only about onehalf the length of a standard length of pipe, is filled in or crowned with sections 29 preferably made of corrugated galvanized iron in the form of half cylinders to rest upon the tops of the layers 5 and intermediately overlap so that the corrugations serve as locking means. Then the final batch of concrete is applied and allowed to harden, permanently embedding the sections 29 and thereby completing the junction of the two long sections of pipe.

The planks produce a step receptacle for the lower edge of the final batch of concrete 6, 26, forming the top of the pipe, and in the case of non-pressure pipe there is thus produced a strong and reliable joint not liable either to crack or to leak.

It has been heretofore proposed vto employ a rubber tube supplied with air pressure to form a collapsible mold and such a mold may be used in the formation of the concrete pipe in accordance with the` present invention. This being a known expedient, it is unnecessary now to enlarge on it.

To cure the pipe .made in accordance with. the hereinbefore described method, water should be turned into it after the necessary length of pipe is laid, say from one-half mile y to a. mile, not later than about fifteen days after it is laid and not sooner than fortyeight hours after any of it is built.

To keep the molds from floating up on the concrete as poured, two large flat rocks 29a already referred to, and one of which is shown in Fig. ll, are embedded in the bottom of the trench and secured to the mold 3y a strand or strands of wire 30; and when the mold is contracted and pulled, these rocks are permitted to remain in the trench, being spaced about two feet from either end of the mold. This, however, is only necessary where the temperature prevailing during the formation of the pipe ranges from F. down to 30 ll. The rocks serve the function of anchors.

Where slip joints occur, the oiling` treatment is employed toprevent sticking of the fresh concrete thereto. The slip joints may be dipped in coal tar or other substance to preserve them. The molds are painted with a mixture of oils before the concrete is poured on them. lf desired, an extra thickness of cement may take the place of reinforcements.

ln Fig'. l2, reinforcements 3l of circumferential type are shown. These reinforcements are made of metal mesh of half cylindrical contour with the meeting edges formed into hooks, and the hooks of one reinforcement interlocking with those of the other lengthwise of the pipe. Such reinforcements are, however, not needed in pipe under 24 in. in diameter, for the method of making concrete pipe by adding extra concrete and making the walls of the pipe thicker according to pressure to be put on is cheaper than to reinforce with iron and is just as strong.

V] hat I claim is l. The method of laying concrete pipe, which consists in locating molds at distantly separated points, pouring concrete about the respective molds to produce lengths of pipe, then elongating the pipe thus formed in both directions by withdrawing and resetting the molds next to the pipe already formed and again pouring concrete about the reset molds in turn to prolong the pipe, and repeating the operation until the ends of the progressively prolonged pipe sections are brought nearly into juxtaposition, each pipe lengt-h at its free end being coated with an oily composition before the next length is poured, to prevent the two juxtaposed ends from knitting together, and finally coupling the adjacent ends of the pipe by a final pouring of concrete, so that the pipe forms one continuous substantially monolithic form.

2. The method of laying concrete pipe, which consists in locating molds at distantly separated points, pouring concrete about the molds successively to produce respective lengths of pipe, then prolonging the formed pipe in each direction by witl drawing and resetting the molds adjacent the end of the pipe already formed and again pouring concrete successively about the reset molds, and repeating the operation to each pipe end in turn until the approaching ends are brought nearly into juxtaposition, and finally coupling` said ends to-V gether byV a final pouring of concrete, the last pouring being about a mold which re'- mains permanently in place, whereby a continuous pipe is formed which is substantially monolithic. c

3. The method of expediting the formation and laying of concrete pipe and preventing injury Yto the pipe from expansion lll() and contraction, consisting in pouring a concrete mixture ot suitable consistency about molds located at widely separated localities in the line ot the completed pipe, elongating the pipe by progressively and retrogressively continuing the formation ot the pipe until the ends of the pipe are in close juxtaposition, and completing the pipe into a substantially monolithic whole also lby pouring the concrete, and providing slip joints interposed between the pipe sections formed by each pouring, whereby to avoid buckling and cracks in t-he length of the pipe due to expansion and contraction.

t. The method of laying concrete pipe which consists irst in digging a trench of considerable length to permit start-ing the building oit the pipe simultaneously at sev eral distant points along the trench, locating the molds in the trench at spaced intervals, forming sections of pipe about the molds by pouring a basic layer ot' a` concrete mixture in the bottom ot the trench underneath the molds, pouring another layer on top otl the first layer and extending part way up the sides ot the molds, and then pouring a final layer drier than either of the other layers over the molds to form the top of the pipe, then withdrawing the molds of a previously constructed section of the pipe att-er the concrete has set, then placing the molds at the ends of the completed pipe section and continuing the pouring of the concrete about the molds with the operation proceeding both progressively and retrogressively until the intervals between the originally omed pipe lengths are nearly closed, and thon pouring the concrete to produce a junction pipe secn tion bridging the interval between the juxtaposed elongated pipe ends, whereby there is formed a substantially monolithic concrete pipe ot any length.

5. rI`he method of laying concrete pipe which consists first in digging a trench of considerable length to permit starting the formation of the pipe at numerous relatively distant points along the trench, placing molds in the trench at spaced intervals,

forming the pipe about alternate molds spaced from each other, withdrawing the molds after sufficient setting ot the concrete, placing the molds at the ends of the completed pipe sections and continuing the pouring of the concrete about the molds until the intervals between the originally formed pipe lengths are completed to an extent bringing the formed pipe ends into close approach, next pouring the concrete to produce a junction pipe bridging the interval between the juxtaposed elongated pipe sections whereby there is formed a substantially monolithic concrete pipe ol any length and including slip joints as a permanent part ot` the pipe structure between certain ones otl the sections of concrete pipe.

6.*The method of laying concrete pipe which consists in producing the concrete pipe in mold lengths by pouring successive layers of concrete ot sloppy mix which will flow without tamping about the bottom and sides of the molds and iinishing the pouring with a drier concrete mix which will absorb moisture from the lower concrete pourings and will avoidy the running of Water along the top of the formed concrete which would injure new concrete, and prolonging the pipe progressively and retrogressively, and finally joining the prolonged pipe sections when near juxtaposition whereby the pipe 'from end to end is substantially monolithic.

7. The method of forming concrete pipe in a trench, which consists in providing anchors in the bottom otl the trench, pouring in a layer of concrete of sloppy mix which is wet enough to How without tamping, then setting the mold and tying the same to the anchor to prevent the mold from being lifted by the hydrostatic pressure of the concrete, then pouring in another layer ot the sloppy mix around the sides of the mold, and then completing the pouring ot the pipe section by a layer of drier mix which will absorb water from the lower layers.

In testimony that I claim the foregoing as my own, I have hereto aflixed my'signature.

THOMAS DE LA MARE. 

